A microbicidal and antiseptic agent used in hospitals etc. may be a viscous gel composition obtained by adding a thickener to a microbicide solution for the purpose of preventing the agent from spilling when taken on the palm or dripping down when rubbed into the hand.
For example, JP-B-7-29884 and JP-A-11-9667 describe microbicidal and antiseptic agents obtained by adding a carboxyvinyl polymer as a thickener to an alcoholic solution. Also, Japanese Patent Nos. 3499882, 2533723 and 3456236 describe microbicidal and antiseptic agents obtained by adding a carboxyvinyl polymer and a cellulosic polymer compound as thickeners to an alcoholic solution.
However, these thickeners cannot sufficiently increase the viscosity of the composition when the alcohol concentration is high, and adding increased amounts of thickeners for higher viscosity causes twisted semisolid of the composition when applied to the hand. Also, antiseptic agents with these thickeners are sticky and uncomfortable when used.
Meanwhile, JP-A-2000-86408 describes a microbicidal and antiseptic gel agent comprising an alcoholic solution, a resin polymer such as a carboxyvinyl polymer and glucomannan. When the microbicidal and antiseptic agent is rubbed into the hand, as the agent loses its water, the glucomannan component becomes a rubbery material and is left as a residue like twisted thin paper strings. Dirt on the hand is attached to the residue and, as a result, removed. The document also describes that agar and/or a cellulosic derivative may be added in order to enhance the effect of the gel composition. However, since this microbicidal and antiseptic agent leaves a residue composed of glucomannan after rubbed into the hand, dry touch cannot be obtained.
In addition, Japanese Patent No. 3531735 describes a microgel that can be used as a thickener. The microgel with an average particle size of 0.1 to 1 μm is obtained by dissolving a hydrophilic compound having gelation ability such as agar in water, cooling the solution for gel formation, and then pulverizing the gel. It is said that a composition to which the above-mentioned microgel thickener is added is not sticky and that the viscosity thereof does not decrease even when a large amount of pharmaceutical components or salts are comprised. The microgel thickener is expensive since it is produced by a complicated method.